Messages in this thread | | | Date | Tue, 9 Sep 2014 22:21:05 -0700 | Subject | Re: [Patch v4 1/2] freezer: check OOM kill while being frozen | From | Cong Wang <> |
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On Tue, Sep 9, 2014 at 1:48 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > On Wednesday, September 10, 2014 12:23:36 AM Tejun Heo wrote: >> On Tue, Sep 09, 2014 at 05:16:55PM +0200, Michal Hocko wrote: >> > But OOM killer doesn't kill kernel threads as they do not own any >> > memory. So the check should be safe, no? >> >> Even for userland tasks, try_to_freeze() can currently be anywhere in >> the kernel. The frequently used ones are few but there are some odd >> ones out, and, again, there's nothing enforcing any structure on >> try_to_freeze() usage. The other thing is that we may do quite a bit >> during exiting including allocating memory. Are those safe for system >> PM? Rafael, what exactly are the rules for PM? What shouldn't >> change? > > We can't make any assumptions regarding the availability of any devices. > That is, whatever can end up in device access may potentially fail. >
So we still have to rule out PM freeze, right?
I am thinking about adding a new task flag or adding a new parameter to __refrigerator() to distinguish PM freeze with cgroup freeze. Will try to code tomorrow.
Thanks!
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